1. Field of the Invention
The present invention relates, in general, to scanning apparatuses using a vibration light modulator and, more particularly, to a scanning apparatus using a vibration light modulator, which performs high speed scanning using a plurality of diffracted beams formed through the light modulator, and allows each of the diffracted beams to form a plurality of pixels by vibrating the light modulator.
2. Description of the Related Art
Printer technology has been developed toward high speed, miniaturization, high quality and low cost. Typical printers employ a laser scanning scheme of scanning laser beams using a Laser Diode (LD) and an f-θ lens.
In order to realize a high speed printer, an image head scheme using a multibeam type beam generation device is used. In such a scheme, high speed and high quality characteristics can be realized, but the cost increases due to the use of a plurality of light sources.
FIG. 1 illustrates an example in which a conventional laser scanning scheme using a single light source and an f-θ lens is used. As shown in FIG. 1, an example of the operation of the laser scanning scheme is described below.
If a light beam is generated by a Laser Diode (LD) 10 in response to a video signal and passes through a collimator lens 20, the light beam is converted into collimated light. The collimated light is converted into linear light parallel to a scanning direction by a cylindrical lens 30, and the linear light is incident on a polygon mirror 40.
As described above, if the linear light parallel to the scanning direction is incident by the cylindrical lens 30, the polygon mirror 40, rotated by a motor, scans the incident linear light in the direction of an f-θ lens 50.
Thereafter, the linear light scanned at a constant angular velocity by the polygon mirror 40 is deflected by the f-θ lens 50 in a scanning direction, the aberration of the deflected linear light is corrected, and the corrected light is scanned onto the scanning surface of a photosensitive drum 60 at a uniform velocity.
In the laser scanning scheme, it is difficult to attain a high printing speed due to problems related to the low switching speed of the laser diode 10 and the scanning speed of the polygon mirror 40.
That is, in order to increase the scanning speed of light beams, the polygon mirror 40 must be rotated using a higher speed motor. However, the higher speed motor is expensive, and the motor rotating at high speed causes heat, vibration and noise to incur problems such as the deterioration of operating reliability, so that a great improvement in scanning speed cannot be expected.
In another method of increasing the speed of an optical scanning apparatus, there is an image head printing scheme using a multibeam type beam generation device.
That is, as shown in FIG. 2, an array 80 of many Light Emitting Diodes (LEDs), the number of which is sufficient to fill printing paper, is constructed in an image head 70 to form a plurality of beams, so that one line can be simultaneously printed without using a polygon mirror and an f-θ lens, unlike the laser scanning scheme, thus markedly increasing printing speed.
However, if a plurality of LEDs is used so as to construct the LED array 80, the cost increases, and light uniformity between LEDs in the array is decreased, so that it is difficult to obtain uniform images.